Road machine



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l RQAD MACHINE Filed Aprilr2'7, 1951 15 Sheets-Sheet 13 Feb 6, 1940. c. A. GusTAFsoN 4 ROAD MACHINE File d April 27, 1931 15 Sheets-Sheet 14.

C. A. GUSTAFSON ROAD MACHINE Feb. 6, 14940.

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Patented Feb. 6, 1940 UNITED STATES' PATENT OFFICE 2,189,286 ROAD MACHINE Application April 27, 1931, Serial No. 533,179

28 Claims.

My invention relates to road machines and particularly to graders. It is an object of the invention to provide an earth working machine in which the earth engaging tool is capable of a wide range of adjustments, is flexible in use and designed to be easily controlled by the operator.

Another Aobject of the invention is to provide a road machine of improved construction and having an. earth engaging tool adapted to be positioned to make a high-angle cut.

Another object is to provide a road machine having a plurality of adjusting means which are adapted to position an earth engaging tool to make a high-angle cut.

Another object is to provide a road machine having a plurality of adjusting means which are adapted to adjustan earth engaging tool to plowing position. Another object ofthe invention is to provide 20 a `road machine having means for positioning an earth engaging tool to make a high-angle cut including means for adjusting the length of the supports for said tool.

Another object of the invention is to provide a road machine having means for positioning an earth engaging tool to make a high-angle cut including means for adjusting the length of the supports for said tool and means for equalizing the tensionthereon in all positions thereof.

Another object of the invention is to provide a road machine having means for positioning an earth engaging tool to make a high-angle cut including means for connecting said tool to its supporting frame at a plurality of transverse positions with respect thereto. l

Another object of theinvention is to provide a road machine having means for positioning an earth engaging tool to make a high-angle cut including means for tilting the Wheels with respect to the frame,

Another object of the invention is to provide a. road machine having means for positioning an earth engaging tool to make a high-angle cut including means for adjusting a wheeled support transversely with respect to the road machine frame.

Another object of the invention is to provide a road machine having means for positioning an earth engaging tool to make a high-angle cut including means for varying the limits of transverse movement of said tool with respect to the frame of the machine.

Another object of the invention is to provide a road machine having means for positioning an earth engaging tool tov make a high-angle cut including means for adjusting the angle of said tool with the line of draft and means for locking said tool in adjusted position.

Anotherl object of the invention is to provide a road machine having means for positioning 5 an earth engaging tool to make a high-angle cut including means for varying the angle between said tool and the draft connection therefor.

Another object is `to provide an earth working machine having means for -adjusting an earth 10 engaging tool from a vertical depending position to an elevated position on either side of said machine.

Another object of the invention is to provide an earth working machine having means for ad- 15 justing an earth engaging tool to plowing position including means for lowering the front end of said tool.

Another object of the invention is to provide an earth Working machine having a plurality of 20 adjusting means for an earth engaging tool and a unitary, manually operable means for selectively controlling operation of said adjusting means.

Another object of the invention is to provide in a machine of the class described an improved 25 locking means for an adjustable member.

Another object of the invention is to provide a road machine frame of sturdy construction which can be manufactured economically.

y Another object of the invention is to provide 30 a tool supporting circle of a simple and sturdy construction which can be readily formed at a small cost.

` Another object of the invention is to provide an earth engaging .tool which is adapted to act 35 as a plow.

Other objects will appear as the description progresses. y

4 Description of figures Figs. 1 and 2 are general views of the machine. 40

Fig. 1 is a right side elevation.

Fig. 2 is a plan.

Fig. 3 is a side elevation of the rear end on line 3-3 of Fig. 2. 4

Fig. 4 is a section of a detail on line I4 of 45 Fig. 3.

Figs. 5 to 7 illustrate the construction of the front end.

Fig. 5 is a front elevation.

Fig. 6 is a right side elevation from line 6--6 50 of Fig. 5.

Fig. 7 is a vertical longitudinalsection on line 1--1 of Fig. 5. Y

Figs. 8 to 10 illustrate the .construction of the rear end.

Fig. 14 is a similar view showingthe circle unlocked.

Fig. 15 is a section through one circle support on line |5|5 of Fig. 12.

Fig. 16 is a section through another circle support on line |6|6 of Fig. 12.

Fig. 17 is a perspective view of the circle locking pin.

Fig. 18 is a vertical longitudinal section of the circle group with its controls, taken on line |8`| 8 of Fig. 2.

Fig. 19 is a horizontal section of a portion of the adjusting mechanism on line I 9| 9 of Fig. 18.

`Fig. 20 is a transverse vertical section on line 20-20 of Fig, 19.

Figs. 21 and 22 illustrate the compensating spring lift mechanism.

Fig. 21 is a plan.

Fig. 22 is a vertical longitudinal section on line 22--22 of Fig. 21.

Figs. 23 to 25 illustratel the center shift mechanism.

Fig; 23 is a rear elevation from line 23-23 of Fig. 1.

Fig. 24 is a plan from line 24-24 of Fig. 23.

Fig. 25 is a vertical longitudinal section of the center shift control. l

Fig. 26 is a perspective view of the circle assembly,

Fig. 27 is a diagrammatic illustration of blade adjustments obtained by varying the angle between the drawbars and the plane of the circle.

Fig. 28 is a diagrammatic illustration showing adjustment of the blade to a high bank sloping position by changing the lift link lengths and usn ing the wide range center shift.

Fig. 28a is a diagram of the-kinematic chain in Fig. 28.

j symmetrical with respect to the longitudinal axis,

and includes two side channels I0, Il, which extend substantially the length of the machine and have a slight convergence toward the front end (Fig. 2). These side channels are interconnected by cross members and braces.

At the front end of the machine (Figs. 1, 2, 5. 6, 7) plate I2 is riveted to the forward ends of side channels I0, II. AngleV I3 at the front edge of plate |2 is riveted to plate I2 and to side channels I0, I I. Beneath plate I2 is bracket I4 having central horizontal portion |5 provided with boss I6, and having vertically extending portions I1, I8, which are riveted inside the forward ends of side channels I0, respectively. A framework comprising members |9, 20, 2|, 22, 23, 24, is secured to the front end of the frame as a support for a mechanism to adjust -the line of draft of 1y, by plates 3|, 32, and by straps 33. T-bar 34 has its ends 'overlapping 4straps 33, and is secured to the lower edge of plate 25. To the rear ends of extensions 21, 28 is secured angle 35. Vertical posts 36, 31 are secured to the inner sides of side channels I0, I, respectively, and serve to support a portion of the blade lifting mechanism. Channel 38 is secured to the lower ends of posts 36, 31, and in addition to reinforcing the framework serves in conjunction with inverted U-bracket 39 to support platform 40, the forward edge 4| of whichextends through aperture 42 in plate 25. A framework, consisting of bar 43 secured to post 31, bars 44, 45 secured to angle 35 and interconnected by strap 46, supports part of the mechanism for tilting the rear wheels.

In the central portion of the machine above the blade (Figs. 2, 3, 11, 23, 24) the ends of a pair of spaced apart angles 41, 4B are secured to the top faces of .side channels I0, and the connections are reinforced by gussets 49, and angles 5|, 52.

Angles 41, 48 also serve to support part of the blade lifting mechanism. The ends of a pair of spaced apart angles 53, 54 are secured to the bottom faces of side channels I0, beneath angles 41, 48; the central web of T-bar 55 is interposed between angles 53, 54 and is secured thereto. Angles 53, 54 and T-bar 55 support the center shift mechanism. The central portion of side channels I0, are further reinforced by angles 56, 51 which are secured to the inner lower edges thereof and extend rearwardly to posts 36, 31 to which they are also secured.

Intermediate the front end and the central cross members(Figs. l, 2, 21, 22) is cross member 58 which is fabricated, having a substantially I-beam cross section and end anges 59, 60 for securing it to side channels I0, The connections of cross member 58 with the side channels is reinforced by gussets 6|, 62. Cross member 58 also serves as a support for part of the compensating spring mechanism.

To obtain rigidity and to prevent weaving, diagonal braces 63, 64, 65, 66, 61, 68 are employed, as shown in Fig. 2. Cross pieces 69, 10, 1| are connected to side channels I0, I| to provide supports for adjusting mechanisms.

Front wheels .(Sheets 4, 5 and 10) (100 series numerals) Front wheels |00, |0| (Fig. 5) are journaled on spindles which are integral with bell cranks |02, |03, pivoted at |04, |05,in angles |06 (Fig. 6) which comprise the front axle. Upwardly converging channels |01, |08 are secured at their lower ends to angles |06 and at their upper ends to casting |09, having boss I0 (Fig. 7) apertured at and contacting the under side of boss I6 in the horizontal portion I5 of frame bracket I4.

Hollow kingbolt ||2 passes thrcugh aperture and is supported in boss I6 through which it passes, and at ||3, ||4 in housing 5 which is provided with ange ||6 for attachment to plate |2 of the main frame. Nut I2 is threaded to the lower end of kingbolt ||2 and is adapted 75 to be locked thereon. The front axle and wheels pivot on the vertical axis of the kingbolt.`

The front wheels can .be tilted with respect to the front axle by rocking bell cranks |02, |03 (Fig. 5) on their pivots |04, |05. For this purpose the upstanding arms ||1, ||8 of bell cranks |02, |03 are pivotally connected to shift bar ||8. Movement of shift bar- ||9 will impart equiangular oscillations to the bell cranks. To facilitate operation of shift bar ||9, a strap is pivotally connected to `axle |06 and lug ,|2| secured to the shift \-bar.

To operate shift bar ||9, sector |22 is secured thereto and meshes with pinion |23 (Fig. `6) on |21 by an extensible driving connection comprising square shaft |29 telescopically' engaging within hollow square sleeve |30. Sleeve |30 has a universal connection |3| with shaft |28, and shaft |29 has a universal connection |32 with worm shaft- |21. Rotation of shaft |28 effects rotation of worm |21, worm wheel |26, shaft- |24, pinion |23, to shift bar ||9 to tilt the wheels. The extensible universal connection between shaft |28 and worm 121 enables the shift bar to be operated in all positions of the wheels and axle.

Shaft |28 (Fig. 7) has bevel gear |33 keyed to its upper end and retained thereon. Bevel gear |33 is journaled at |34 in housing |35 which fits the reduced upper end portion of kingbolt H2 and is secured thereto by means of lock bolt |36. -Bevel gear |33 is driven by bevel pinion |31.keyed to shaft |38 which is journaled at |39 in housing and is provided with` sleeve |40 received in housing |35 at 4|. Shaft 38 is retained in place in housing |34 by means of nut |42 and yoke |43, which is secured to shaft |38 and forms part of universal joint connection |44, the other yoke |45 of which is secured to shaft |46. The rear endof shaft |46 is supported at 141 (Fig. 18) in support 69, where it is connected by universal joint' |48 to telescopic shaft |49 which is connected by universal joint |50 to stub shaft |5| (Fig. .19) vjournaledv in housing |52 secured to support 10. Within housing |52, shaft |5| has secured thereto gear |53 which is adapted to be driven by pinion. |54 splined on sleeve |55 to which operating crank |56 is secured. Pinion |54 is adapted to be driven by sleeve |55 and to be axially adjustedv thereon for a purpose hereinafter described. y When pinion |54 is in mesh with gear |53, rotation of crank |56 causes tilting of the front wheels.

Rear wheels (Sheets 3, 6 and 7) (200 series numerals) `2|3, 2|4 to brackets 206, 201 by welding to provide continuous flanges along the bottom edges of the axle for cooperation with guides 2|5, 2|6, 2| 1, 2|8 on main frame extensions 21, 28.

Rear axle 208 is transversely adjustable with respect to the main frame. For this purpose, rack 2|9 (Fig. 9) is secured to the rear face of I-beam 208 and pinion 220 is arranged to mesh therewith. Pinion 220 is operated in unison with worm gear 22|. Shaft 222 on which they are secured is journaled in housing 223 which has a depending portion 224 secured to the upstanding web of frame angle 35. Worm gear 22| (Fig. 10) is driven by worm 225. Worm shaft 226 is journaledin housing 223 and is operated by crank 221. Axle 208 can be shifted transversely of the main frame by operation of crank 221..

The rear wheels can be tilted with respect to the rear axle. For this purpose, the upstanding arms 228, 229 (Fig. 8) of bell cranks 202, 203 are interconnected by shift bar 230 which is guided by strap 23| and shifted by pinion 232 (Fig. 3) and sector 233, the latter being secured to bar 230. Pinion shaft .234 is journaled in housing 235 within which worm gear 236 (Fig. 8) is secured to the shaft. Worm 231 meshes with worm gear 236 and worm shaft 238 is also journaled in housing 235. Rotation of worm 231 causes bar 230 to begshifted to tilt the wheels with respect to the axle.

Worm 231 is operated by crank 239 whose shaft 240 is journaled in housing 24| supported onframework 43, 44, 45. Secured to shaft 240 within housing 24| is bevel pinion 242 which drives gear 243, the latter being secured to a short vertical shaft 244, the lower end of which is connected by universal joint v245 to square hollow sleeve 246 'within which is received square shaft 241, the lower end of which is connected by universal joint 248 to worm shaft 238. Rotation of crank 239 results in tilting the wheels, and due to the extensible universal joint connections between shaft 244 and shaft 238, the wheels can be tilted by crank 239 in any position of the wheels or axle.

Blade and circle (Sheets 5, 8, 9, 10, and 13) (300 series numerals) Blade 300 (Fig. 18) consists of cutting edge 30| secured to moldboard 302 and end bits 303, 304 (Fig. 11) secured to moldboard 302 and overlapping cutting edge 30|. Angle bracket 305 (Fig. 18) is secured to moldboard 302 and angle 306 is secured to the trailing edge of angle 305. Brackets 301, 308, 309, 3|0 (Fig. 12) are secured to angle bracket 305. Corresponding v"brackets Brackets v301'-3|4 areused for connecting the blade to the circle assembly in different positions.

Circle 3|5 (Fig 26). is made of a single piece of angle bent into a circle with the ends joined by welding at 3|6. Beam` 3|1 has a central portion 3| 8 which is bent into a semi-circle of substantially the same radius as the circle'. This central semi-circular portion of the beam encompasses approximately one-half of the circle and is riveted thereto. End portions 3|9, 320 of beam 3| 1 extend tangentially from the circle and downwardly, their lower ends being apertured at 32|, 322 for connection to the brackets on angle 305 by means of pins 323, 324. In order to rigidly connect the ends of the beam.to the circle,

brackets 325, 326nare riveted to end portions 3|9, 320. The upper ends of the brackets 325, 326 are riveted to the ends of channel4 321 which is rigidly connected to circle 3|5 by brackets. 328, 329. In addition, the lower `end of brackets 325, 326 are rigidly secured by gussets 330, 33| to the lower ends of inclined braces 332, 333, the inner ends of which are riveted to channel 321.

' 'Ihe inner faces of links 334, 335 are serrated at 338, 339 to engage with corresponding serrations in clamping blocks 340, 34| on the beam. A plurality of brackets 301 to 314 is provided so that the blade may be connected to the beam in different transverse positions with respect to the surface so that the blade can be made to extend farther outwardly to the left or right of the machine as desired. There are two pairs of these brackets which do'not appear in F'ig- 12 because they are beneath the circle.

The circle is revolvably mounted in a frameywork (Fig. 12) consisting of forwardly converging side bars 342, 343 and rear cross bar 344. The rear end of side bar 342 is rigidly connected with the right end of bar 344 by bracket 345 to the webs 346, 341 of which they are bolted. Similarly the rear end of side bar 343 is rigidly connected with the left end of bar 344 by bracket 348. The front ends of the side bars are secured to a hollow connection block 349 (Fig. 18) in which is pin 350 for a purpose hereinafter described. The intermediate portions of the s'ide bars are rigidly connected together by casting 35| (Fig. 12). The inwardly extending flange of the circle rests on an arcuate ledge 352 (Fig. 15) which is formed integrally with bracket 348, and above the rear end of ledge 352 a portion of the bracket is extended over the inwardly projecting flange of the circle where it is provided with a boss 353 adapted to receive a rub iron 354 and an adjusting screw 355 therefor, which is threaded in boss 353 and provided with lock nut 356. The arcuate ledge provides a support for the circle on which the circle can be revolved and the rub iron serves to take up wear in the parts and to reduce the amount of. play between the circle and the support. Bracket 345 is similarly equipped. Like- Wise, a ledge 351 .(Fig 16) is provided under the front right corner of casting 35| to support circle 3|5 and an adjustable rub iron 358 is associated therewith. The casting is similarly constructed at the left front corner. Thus, four arcuate ledges, arranged in a circle, are provided on the circle supporting framework which permit the circle to be revolved thereon, and there is an adjustable rub iron associated with each support.

The circle supporting framework is connected by drawbars 359, 360 (Figs. 12 and 18) to the front end of the main frame (Fig. 7) where horizontal portion. i of U-bracket |4 has a rearwardly extending fork 36| secured thereto. Drawbars 359,360 converge forwardly to a connection 362 to which they are bolted. In connection 362 is a bolt 363 having an apertured head 364 which is connected by pin 365 in fork 36|. Bolt 363 can swing in a horizontal plane about the vertical axis of pin 365, and,due to the rounded edges of the aperture in the head 364 and the wide spacing of the jaws of the fork 36|, bolt 363 is capable of a limited oscillation in the Vertical plane, as well. The rear end of drawbar 360 is pivotally connected to the circle supporting framework at 366 (Fig. 12) and the rear end of drawbar 359 is pivotally connected thereto at 361. By reason of these pivotal connections between the drawbars and the circle supporting framework, the framework, together with the circle and the blade, can be raised and lowered with respect to the drawbars, or, in other words, the angle between the drawbars and the plane of the circle can be varied. Also, the drawbars, together with the circle and blade assembly, as a unit, are capable of a limited universal movement about the intersection of the axes of pin 365 and bolt 363 as a center.

To summarize the movements of adjustment of which the circle is capable, they are, an arcuate movement in a horizontal plane about the vertical axis of pin 365; an arcuate movement in vertical planes containing the axis of pin 365; oscillation about the axis of bolt 363; a jackknife movement between the circle and the drawbars; and oscillation of the circle about its center, The desired circle adjustment is usually obtained by combinations of these movements.

Blade lift (Sheets 3, 8, 11 and 15) (400 series numerals) rlhe ends of rear cross bar 344 (Fig. 11) of the circle supporting framework are connected by ball and socket joints 400, 40| to links 402, 403 in the to the forward ends of `shafts 4|0, 4H. Links 402, 404 and 403, 405 are provided with spaced apertures to receive pins 4|2, 4|3 by means of which the telescoping links can be secured together at the desired length. In addition, link 404 can be secured. to link 402 by clamp 4|4, and link 405 can be secured to link 403 by clamp 4|5. 'I'he link connections between the ends of bar 344 and lift arms 408, 409 are adapted to be adjusted at-diiferent lengths for a purpose hereinafter described. The forward ends of shafts 4|0, 4| are supported in bearing brackets 4|6. 4|1 which are supported from the main frame by means of portions integral therewith which extend inwardly between the upstanding flanges of angles 41, 48 and which are riveted thereto. The rear ends of shafts 4|0, 4|| (Figs. 3 and 4) are supported in bearings in housings 4 I8, 4l9 which are secured to posts 31, 36. The rear end of shaft 4|0 has worm gear 420 secured thereto within housing- M8, and worm gear 420 is adapted to be driven by worm 42| on worm shaft 422 which is journaled in housing 4|8. Worm shaft 422 extends inwardly to receive operating wheel 424. Likewise, shaft 4|| is operated by wheel 425 on worm shaft 423 which through its worm drives a worm wheel on the rear end of shaft 4| l.

B`y manipulation of wheels 424, 425 the operator is enabled to raise or lower either end of bar 344.` By reason of the fact that shafts 4m, 4|| at the points at which arms 408, 409 are connected thereto extend outside the main frame (Fig. 28), each of the arms 408, 409 is `capable of assuming a substantially vertically depending position. Due to the fact that the links 402, 404

and 403, 405 are adjustable, the angle of inclina- -capable of adjusting the heavy circle and blade assembly to these extreme angles of inclination, a spring lift compensator is employed. Grooved cams 426, 421 (Figs. 11, 21 and 22) are secured to shafts 4|0, 4H to rotate therewith.

` ments of'lift on the shafts are not equal. Under 23.) on shaft 510, journaled in`housing 511.

'I'he ends of chains 428, 429 are secured by bolts 430, 431 at the outer ends of the grooves in cams 426, 421. Sheaves 432, 433 are supported by arms pivoted in brackets secured to angles 56, 51. Chains 428, 429 pass over cams 426, 421 and down under sheaves 432, 433, from which point they extend forwardly to clevises 434, 435 by which they are connected to the rear ends of springs 436, 431, the forward ends of which are connected by clevises 438, 439 to the ends of chain 440 which passes around sheaves 441, 442. -These sheaves are journaled in bracket 443 which is secured to cross member 58. Clevises 434, 438 are interconnected by safety cable 444, and clevises 435, 439 are interconnected by safety cable 445. 'I'hese 'cables prevent the springs from flying in the air if they break. By reference to Fig. 1 1, it will be seen that the cams are so proportioned and arranged on the shafts that as the arm moves from the vertical depending position to the horizontal position, the leverage of the cam is increasing, that is, the radii from the shaft center to the cam surfaceincrease in length with the angle of lift. The `cam profile is designed to maintain torsional balance in the shaft. ,While the lift arm radius is constant andthe lift force along the axis of the link may in the case of a straight vertical lift be considered substantiallyv constant, the moment about the axis of the shaft increases as the arm moves from the vertical `depending position to the horizontal. The

the blade when the blade is. positioned directlyA under the machine, when the blade is swung to the side of the machine to obtain a steep angle of inclination to the ground as shown in Fig. 28, the link tensions are unbalanced and the mothese circumstances, equilibrium is nevertheless obtained because the springs of the equalizer are interconnected. In fact, the two lift arm shafts Circle Shift (Sheets 1, 8 to 10, and 12 to 16) (500 series numerals)4 Means areprovided for (1) shifting the center of the circle transversely of the machine or about l the center of pin 365; (2) shifting the circle on its own center, and (3) adjusting the plane of the circle with respect to the drawbars.

(l) For shifting the center of the circle, the supporting frame of the circle is adapted to be variously connected by a link to a rack on the main frame which can be slid transversely of the main frame. Rear cross bar 344 (Fig. 1l) of the circle supporting framework is provided with apertures 500, 501 adjacent its ends for connection to a link 502 having a hooked end for connection with apertured lugs 503,V 504, 505 depending from rack 506 which has channels 501, 508 (Fig. 18) formed integrally therewith for engagement with the flanges o f T-bar 55, which, as explained before, is secured to the main frame. Rack`506 is adapted to slide along bar 55 and for this purpose is engaged with pinion 509 (Fig.

Keyed to shaft 510 within housing 511 (Fig. 24) is worm gear 512 which is driven by worm 513 on hollow shaft 514, also journaled in housing 5| I. The' rear end of hollow shaft'514 (Fig. 25) is supported in bracket 515 which is secured to cross member 11 in the main frame. The hub 516 of hand wheel 511 is loosely journaled on the rear end of hollow shaft 514. 'The forwardend of hub 516 is formed as a clutch element 518 which is adapted to be, engaged with a clutch element 519 secured by pin 520 to hollow shaft 514 by sliding hand wheel 511 and hub516 in the direction of arrow 514. For normal operation, the center shift mechanism is adjust- `ed as illustrated in Fig. 11 with link 502 engaged with the central apertured lug 504 on rack 506, and with the other end of link 502 engaged with either aperture 500 or aperture 501 in bar 344 depending on the angular adjustment of the circle itself; that is, depending on the angle of the cutting edge with respect to the longitudinal axis of the machine. Hand wheel 511 can be operated to shift rack 506 toward either side of the machine, thereby shifting the center of the circle to extend the blade farther out on either side. By engaging link 502 with lugs 503 or 505, the range of center shift can be further increased, so that a plurality of ranges of center shift are obtained with a single rack. This arrangement is necessary (Fig. 28) to shift the center of the circle well to one side of the machine to obtain extreme angles of inclination of the blade. With the blade inclined at approximately 50 to theaxis of the rear wheel,

almost the entire bladeassembly is outside the Y vertical plane of the side of the frame, as indicated by the line Y-Y. 'I'he lift links alone could not maintain the blade and circle in this position because of. their pivotal connection with the circle supporting frame and the lift arms; but, by the addition of the'center shift link connection, the chain of linkage comprising ('Fig. 28a) the main frame (represented by triangle 406, 401, 503), link 403, 405, link'344 (with which the` circle and blade are a unit), link 402, 404, and link 502, is a locked kinematic chain. Link 402, 404 is pivoted to the frame at 406; link 403, 405 is pivoted to the frame at 401; link 502 is pivoted to the frame at 503. Link `402, 404 is pivoted at 400 to link 344; the other end of link 344 is pivoted to the end of link 502 at 501" and to the end of link 403,405 at 401. In the extreme limit of movement link 502 issubstantially parallel to link 344.

v (2) For shifting the circle on its center, it is provided with an arcuate rack 521 (Fig. 26) secured underneath the inwardly extending flange of circle 315. A pinion 522 (Fig. 18) engages rack 521. Pinion 522 is keyed in the lower end of shaft 523 which is journaled in casting 351 and in housing 524 which is secured to casting 351. Within housing 524 bevel gear 525 is secured to the upper end of shaft 523 and mesheswith bevel pinion 526 secured to shaft 521. Shaft 521 is connected by universal joint 528 to square shaft 529 which telescopes in hollow square shaft 530, the upper end of which is connected by universal joint 531 (Fig. 24) to shaft 532 which passes through hollow'shaft 514. The 

